Yes, it has begun - the war to dwarf all wars before it.
Not only is it UPC vs RMT, but it is UPC vs RMT vs TFE. The three biggest tribes, taking up almost the entire map between them, are now in a dance that will very likely decide the victor of this world.
Fighting has already begun, as UPC launched hundreds of nukes in an very well played assault on Jhupka and managed to take six villages. The cost of those villages was astronomical, but such is the way it is when you're fighting an excellent player backed by a good tribe. In retaliation, Remnant has taken some UPC villages and launched many nukes of their own.
Among them, Hellbound remains allied with UPC, but is currently Neutral towards Remnant (though they are at war with TFE). Should they throw their weight to one side, it could be decisive.
Expect the bashpoints of all participants to skyrocket in the coming weeks.
Good luck, my friends. And let the best tribe win!
Discussions and bets take place here!
Here's a map to show the extent of everything. (dark blue - RMT. Red - UPC. Yellow - TFE. Teal - HB1)
http://static.tw2-tools.com/map_www_us3_3f458fb2fc3648cbc94cbe8f96862677_14368424439618.png